Jared May: What’s Up During the Third Week of June
This upcoming week is going to greet us with increasingly warm weather and potentially many clear nights! With the bright light moon out of the way, it is a great time to observe the universe beyond our home solar system. After this Saturday (The summer solstice), the days will begin to get shorter and nighttime will grow longer. Grab yourself a pair of binoculars or a telescope, a set of seeing eyes, and a lawn chair because this week brings many interesting night-sky objects to observe.
Even without any binoculars or telescopes, there are some brilliant nighttime spectacles to be seen. As the sun is setting, the sky and the clouds tend to get darker as they fall into night. Noctilucent clouds, however, brighten as the sun sets. They shine greatest during astronomical twilight, which begins and ends when the sun is 12° and 18° below the horizon respectively (roughly 10:20 PM to 11 PM). They are bright clouds made of ice crystals that form at roughly 250,000 feet, more than 10 times higher than typical clouds. The dust that is spread throughout the Earth’s upper atmosphere by small meteorites often seeds these clouds.
Noctillucent clouds are somewhat rare and are visible only during the warm months, so be on the lookout!
If you are lucky enough to live in a more rural or less light-polluted environment, then the Milky Way has a treat for you. It rises around 9:30 PM and becomes visible around 10:30 PM when it is fully dark out. The Milky Way stretches from SSE to NNE and passes through the Summer Triangle. The heart of our galaxy, the part with the densest collection of stars, gas, and dust is most visible in the southern direction.
The Milky-Way as seen soon after sunset on June evenings.
Comet PanSTARRS will passing by some notable cosmic landmarks. On June 16, the magnitude 9 comet (fairly faint in a set of binoculars) will pass very close to M109, a barred spiral galaxy located very near the star, Phecda, in the Big Dipper. Around June 23, comet PanSTARRS will be passing by another well-known object near the Big Dipper, M106, another galaxy that can be found by hopping from Dubhe to Phecda to M106, all equidistant.
How to find M109 and M106, where which comet PANSTARRS will be passing near this week.
The majority of stars form as a binary system, so not surprisingly, there are many nearby and bright stars that share the stage with a nearby companion. There are many “optical illusion” binary star systems that are not actually binary stars, but are instead called double stars. All binary stars are double stars, but not all double stars are binary stars. Some bright double stars are sometimes just two bright stars that are very far apart but appear very close to each other in the sky from Earth. One of the more famous true binary stars is Albireo. It is a bright blue star that has a bright red companion and is seen best with a telescope. It is located between Vega and Altair, the two southern-most stars in the Summer Triangle, and forms the “beak” of Cygnus the Swan. (Indeed, the word “alberio” is Arabic for “the beak”.)
Another great double star can be found in the Big Dipper. The second, or middle, star of the handle is actually a bright binary pair, Alcor and Mizar. They were the first binary pair ever to be known and can even be resolved without binoculars or telescope. However, through a telescope, the brighter of the two, Mizar, is seen to itself be a double. And, not visible at the eyepiece, each of those stars are themselves an unresolved pair. The Mizar/Alcor system is like a fairground ride.
The skies will continue to hold many wonders that rise and fall with the seasons. Hopefully the weather holds out for us sky-watchers for the upcoming few days. Until next week, clear skies!